I have a fresh build of minimal CentOS 6.2 on my server.I built the OS on a set of software mirrors created in the OS install process.The system boots and works fine, but I get the following two errors at boot time:

Welcome to CentOS Avvio di udev: udevd-work[395]: error opening ATTR{/sys/devices/virtual/block/md0/queue/iosched/slice_idle} for writing: No such file or directoryudevd-work[395]: error opening ATTR{/sys/devices/virtual/block/md0/queue/iosched/quantum} for writing: No such file or directory [ OK ]

No other message appear.I have made many times software RAID 1 in Centos 5 and I never had any problem.I have read many posts but I haven't found nothing usefull.Surely I have a simple error, but I don't know what or where is it.

Everything works fine thanks, but I want to know why udev displays this message.I do not understand because it shows that error on md0 and not on md2.The two directories:/sys/devices/virtual/block/md0/queue/iosched//sys/devices/virtual/block/md2/queue/iosched/not exist in the filesystem, but udev displays the error "No such file or directory" only on md0 device.Why?

I know that this is an old post, but the same thing started happening to my system when I replaced a failing hard-drive in my raid-1 array with a ssd drive. Apparently it relates to I/O tuning which can be setup in CentOS6.